Unraveling the Effect of Conformational and Electronic Disorder in the Charge Transport Processes of Semiconducting Polymers

Annabel R. Chew, Raja Ghosh, Viktoria Pakhnyuk, Jonathan Onorato, Emily C. Davidson, Rachel A. Segalman, Christine K. Luscombe, Frank C. Spano, Alberto Salleo

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Charge transport in semiconducting polymers is inextricably linked to their microstructure, making the characterization of polymer morphology at all length-scales essential for understanding the factors that limit mobility in these materials. Indeed, charge transport depends both on the ability of polarons to delocalize at the approximately nanometer length-scale and navigate a complex energetic and morphological mesoscale landscape. While characterization of the mesoscale morphology of polymers is well-established, studies of the local chain packing and nanoscale disorder, which affect delocalization, can be significantly more difficult to carry out. Through infrared charge modulation spectroscopy and theoretical modeling, the effect of the local chain environment on polaron delocalization is directly measured and quantified. Using a series of polymers based on the model system, poly(3-hexylthiophene), the link between disorder and polaron localization is systematically explored. Polaron delocalization is correlated with known trends in mobility, revealing that while charge delocalization is always beneficial, the formation of tie-chains is necessary to reach the highest mobilities in semicrystalline polymers. The results provide direct evidence for the importance of both nanoscale (charge carrier delocalization) and mesoscale (tie-chains) orders, demonstrating the need to distinguish the key length-scale limiting charge transport in the design of new, high mobility polymers.

Original languageEnglish (US)
Article number1804142
JournalAdvanced Functional Materials
Volume28
Issue number41
DOIs
StatePublished - Oct 10 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Keywords

  • carrier mobility
  • charge delocalization
  • charge transport
  • polarons
  • structure–property relationships

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